Several years ago I had the pleasure of interviewing Jackie Chan in his London hotel. I say pleasure, but it was a bizarre experience. Chan constantly referred to himself in the third person, insisted that "everybody like Jackie Chan" and outlined his plan to become a major Hollywood actor "like a Robert De Niro or Dustin Hoffman". In the next breath he poured scorn on all those wussy American stars who refused to do their own stunts. "They are replaceable," he said. "But nobody can replace Jackie Chan."

That assertion is now under attack with the news that a Hong Kong stuntman claims to have done just that - standing in for the actor on at least one unnamed Hong Kong production. Predictably, Chan's office has returned fire, pointing out that the actor only occasionally employs a stunt double for his Hollywood roles and only then under extreme duress, as a sop to the insurance companies. Aside from that he remains very much the real deal. A Jackie Chan action flick does exactly what it says on the can.

It comes as no surprise to learn that the fiftysomething Roger Moore didn't really jump out of all those planes during his dotage years as 007. Nor that the likes of Clint Eastwood, Bruce Willis and Sylvester Stallone may sometimes resort to younger men to perform certain cinematic duties.

But the 52-year-old Chan hails from an altogether different school. His brand of cinema is the natural extension of vaudeville or circus acrobatics. His reputation is founded on absolute authenticity. To hear that it might not have been Jackie Chan abseiling on that speeding train is like discovering that Houdini didn't really get out of that box, or that Roger Bannister hired a lookalike to run the four-minute mile.

All told it's been a rough-and-tumble 12-months for the cuddly maestro of chop and sock. The last time I remember him being in the news was when he invaded the stage at a Tawainese pop concert, apparently drunk as a skunk, and invited all hecklers to "go to hell". Such antics bely his clean-living reputation and perhaps suggest that all is not well in his world.

But before we become too tickled by this state of affairs, it is worth reflecting on the peculiar demands of being Chan and considering whether anyone else would be remotely up to the task. As an impoverished child he came within a hair's breadth of being sold to a visiting doctor for the sum total of $26. As a man, he has broken virtually every bone in his body in the pursuit of his art. I wouldn't presume to take on a Jackie Chan role, not for all the stunt doubles in China. Last week I turned my ankle on the street outside work. It still pains me when I walk too fast.